Density-weighted mean wind

From Glossary of Meteorology

density-weighted mean wind

The wind vector representing an average speed and direction over an atmospheric layer of finite depth, accounting for changes in air density over the depth of the layer. The contribution of density generally makes this a superior estimate to a standard mean wind estimate, since winds at heights with higher density (i.e., nearer to the surface) will contribute more to the average value than those at heights with lower density (i.e., at higher altitudes); per unit volume, more air molecules at lower altitudes contribute to the mean wind than those at higher altitudes.

Density-weighted mean wind is commonly used as an estimate of the steering current of a thunderstorm contained within the vertical layer.

Mathematically, the density-weighted mean u and υ wind components are calculated according to Houston (2017):

Density-weighted mean wind.gif

where ρ(z) is the density at height z, h and H are the lower and upper heights, respectively, of the layer over which the average is being computed, and u(z) and υ(z), are the values of the u and υ wind components at height z.

Houston, A.L., 2017: The possible role of density current dynamics in the generation of low-level vertical vorticity in supercells. J. Atmos. Sci., 74, 3191–3208, https://doi.org/10.1175/JAS-D-16-0227.1.


Term edited 3 December 2021.


Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact permissions@ametsoc.org. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.